Alien: Giger's second design for a humanoid alien concept

a) Giger's second version of the stage III of the man in the suit alien paintings were of the creature with a pale elongated insect like human body. (see also: Alien: Jack Kirby's Living Totem as reference for the alien suit)

b) The tongue appeared to start out as elongated and curved up at the end like an Egyptian brain hook for debraining corpses in the mummification process. But later in this painting, the tongue became tubular with a sharp point on one side and a protruding spine sticking out ready to puncture its victim.

Alternate to Alien Stage III, second version, with a row of back pipes and perhaps with an Egyptian brain hook type tongue (source: Alien Evolution documentary)

Egyptian brain hook

c) Tentacles or spines sticking out of the lower part of the back stood nearly vertical in the final version of this although at one point it has a row of four pipes sticking out of the back.